Identification of crude oils by synchronous fluorescence techniques

Fluorescence spectroscopy is a highly sensitive and specific method for oil identification since petroleum oils contain a mixture of many fluorescent aromatic hydrocarbons. Because of this complex mixture, the spectral distribution and the intensity of the fluorescence will vary with the chemical composition of the oil. Therefore at fixed instrumental conditions and a given concentration of oil, the fluorescence spectrum results in a characteristic "fingerprint" of a given oil. The first part of this work involved the development of a library of fluorescence spectra for model aromatic compounds common in environmental samples. The techniques utilized were based on synchronous fluorescence whose advantages in oil identification have been demonstrated. Extensive studies were carried out using the relatively new and little used technique of variable angle synchronous fluorescence (v.a.s.f.). Non-linear v.a.s.f., where the angle of scan trajectory is altered during a scan. was developed as a means of obtaining desired "sections" through the excitation-emission matrix. Good selectivity and calibration linearity were observed for mixtures of compounds. The results obtained demonstrate the potential of the technique in oil identification. Derivative spectroscopy was applied to enhance minor spectral details in the comparison of closely related samples. The second part of the work involved the application of the previous techniques to real-world samples in the form of crude oils and tar balls. The "fingerprinting principle" is based on the fact that environmental samples of oils can be correlated with possible sources by comparing their stable compositional features. Hence fluorescence studies were performed on several oil samples before and after laboratory weathering. By observing spectral regions where weathering occurs, it was noted that these fluorescence techniques for oil identification could be further improved. Effects of cyclodextrins and micelles. and the process of deoxygenation by nitrogen bubbling and sodium sulphite addition, were investigated as further techniques for discriminating between similar samples and enhancing certain spectral details. Finally, other techniques that have been used in oil identification such as infra-red, thin-layer chromatography, and gas chromatography were briefly examined and their use in a multi-method oil analysis approach discussed

Analysis of the Related Party Transactions in terms of managerial and financial issues for the Kenyan Savings and Credit Cooperatives

Related party transactions are a key factor to the sustainability of Savings and Credit Cooperatives (SACCOs). In view of this fact, loans to directors and staff are viewed as a factor which can greatly influence savings and credit cooperatives into either falling into financial distress or helping them to remain a float and become financially stable entities. The stakeholder theory holds that entities should be managed a manner that will satisfy every stakeholder. The stewardship theory reiterates that managers have the organisation at heart and can it to profitability as if it were their own. However approval of loans and other transactions to managers and staff, may not positively impact the entity. This study was designed to establish the effect of related party transactions on the relationship between board characteristics and financial distress of deposit taking SACCOs in Nairobi County. We applied Descriptive research design on Deposit taking SACCOs in Nairobi County which was identified purposively while a census was conceded for all deposit taking SACCOs in the county. We obtained secondary data from SASRA using a data collection sheet after which we performed panel data analysis by use of STATA software. Findings were presented using tables. The study concluded that related party transactions influenced the relationship between board characteristics and financial distress of Deposit Taking SACCOs in Nairobi County. Related party transactions can be an avenue of causing financial distress and should be kept as low as possible. The regulator should come up with a tool based on Altman’s Z score models to predict financial distress in SACCOs in order to offer timely advice to alleviate more distress and consequent bankruptcy which may lead to closure of SACCOs. Another research may be carried out to establish other factors causing financial distress and how to turn around the SACCOs already in distress

The Mediating Effect of Firm Revenue on the Relationship Between Board Characteristics on Financial Distress of Deposit Taking Saccos in Nairobi County, Kenya

The upper Echelons Theory reiterates the importance of top management in an organization and recognizes that the mangers make decisions that grow the entity. Before the establishment of this theory, the premise was that larger firms which drive high amounts of income, are capable of running themselves without failure. Although Organizations that command large amounts of income are deemed to be successful the upper echelons theory holds that these entities cannot be successful without proper management and guidance by top management where the board of directors in this case is considered as top management organ for SACCOs. Savings and Credit Cooperatives (SACCOs) have evolved over time from mobilizing savings and granting loans to become established entities that provide banking services to their customers. They require good governance to avoid the experience of financial distress. The current research was therefore aimed at establishing the influence of firm revenue on the relationship between board characteristics and financial distress of deposit taking SACCOs in Nairobi County. Large entities command more revenue as compared to small firms. Board Characteristics is of importance to this study because it influences Corporate Governance which according to previous research has shown that the practice helps revolutionize performance of various institutions. The study is guided by upper echelons theory which reiterates the importance of top management. Descriptive research design was adopted while Nairobi County was purposively chosen and a census was carried out on deposit taking SACCOs in the county. Secondary data was collected from SASRA using a data collection sheet and a panel data analysis performed using STATA software and findings were presented using tables. The study concluded that firm revenue does not mediate the relationship between board characteristics and financial distress of Deposit Taking SACCOs. Though firm revenue should be enhanced, governance should be improved since it remains a critical success factor in alleviation of financial distress

The meaning of expenditure actually incurred in the context of share-based payments for trading stock or services rendered

Section 11(a) of the Income Tax Act 58 of 1962 entitles taxpayers to a deduction in respect of expenditure actually incurred, provided that all the other requirements of section 11 and section 23 of the Act have been met. A company may issue its own shares, credited as fully paid up, as a payment for trading stock or services rendered, as was the case in C:SARS v Labat Africa (2011) 74 SATC 1. The question that was raised by this decision is whether the issue of shares constitutes “expenditure” as contemplated in section 11(a) of the Act. It is trite that a share in a company is a bundle of rights which entitle the holder to dividends when declared and to a vote in shareholders’ meetings and that a share does not come into the hands of a shareholder by way of transfer from the company, but is rather created as a bundle of rights for him in the company. In C: SARS v Labat Africa, the Supreme Court of Appeal decided that to issue shares as a payment for goods is not expenditure as contemplated in section 11(a) of the Act. The Act does not define “expenditure”. It has been interpreted in certain cases as a payment of money or disbursement, while it has been interpreted as the undertaking of a legal obligation in other cases. The Labat Africa case has been criticised for its interpretation of expenditure on the grounds that it is contrary to the principle that “actually incurred” does not mean “actually paid”. This research has argued that, in the context of the Labat Africa case, which related to an issue of shares in payment for goods, Harms AP’s judgment was concerned with showing why a share issue is not expenditure. He could not have intended to deny a deduction to transactions such as credit purchases

Influence of Board Characteristics on Financial Distress of Deposit Taking SACCOs in Nairobi County, Kenya

The importance of Savings and Credit Cooperatives (SACCOs) cannot be underestimated. Despite their importance, they are faced with numerous challenges among them financial distress which threatens their very existence. The current research sought to establish the role of board characteristics in the financial distress suffered by Deposit Taking SACCOs in Nairobi County. The study is anchored inter alia on Agency Theory. Descriptive research design was adopted while Nairobi County was purposively chosen and a census was carried out on deposit taking SACCOs in the county. Secondary data was collected from SASRA using a data collection sheet and a panel data analysis performed using STATA software. The findings were presented using tables. The study concluded that there was a relationship between board characteristics and financial distress of Deposit Taking SACCOs where board composition, board education and board tenure have statistically significant and negative influence on financial distress. In conclusion SACCOs need to have lean boards, Board composition should also be improved by including more women on boards, there should be more inclusion of members with high and relevant education credentials, and SACCOs should have term limits for their members while an analysis too based on the Altman’s Z score models should be adopted for SACCOs. Another research may be carried out to establish other factors causing financial distress and how to turn around the SACCOs already in distress

Antimicrobial Activity, Toxicity and Phytochemical Screening of Four Medicinal Plants Traditionally Used in Msambweni District, Kenya

This study was designed to evaluate the antimicrobial activity, toxicity and phytochemical composition of organic and aqueous crude extracts of Zanthoxylum chalybeum Engl. (Rutaceae), Adansonia digitata L. (Bombacaceae), Launaea cornuta (Hocht. ex Oliv. & Hern) C.Jeffrey (Compositae) and Grewia trichocarpa Hochst. ex A.Rich (Tiliaceae) traditionally used by local communities of Msambweni District in Kenya.  Aqueous and organic [Chloroform: Methanol (1: 1)] crude extracts were evaluated for their in vitro antimicrobial activity against Methicillin resistant Staphylococcus aureus (MRSA), Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans using broth dilution and disc diffusion methods. Toxicity was determined using Brine-shrimp larvae (Artemia salina L. nauplii) assay. The crude extracts were screened to determine the presence of flavonoids, alkaloids, saponins and sesquiterpene lactones using standard techniques. It was observed that the organic crude extracts from all the species tested except L. cornuta exhibited dose dependent activity against B. cereus, MRSA, P. aeruginosa and C. albicans. None of the crude extracts showed any inhibition against E. coli. Adansonia digitata and Grewia trichocarpa had LC50>1000 µg/ml and were shown to be non-toxic to Brine shrimp larvae unlike those of Z. chalybeum and L. cornuta which both had LC50<500 ug/ml and were considered to be toxic. Phytochemical screening of the crude extracts showed that alkaloids, flavonoids, sesquiterpene lactones and saponins were present in the four plants tested.The study has shown that A. digitata and Z. chalybeum possess promising antimicrobial activity against microbes of health importance and could lead to the isolation of new and potentially effective antimicrobial compounds. Keywords: Medicinal plants; Antimicrobial activity; Brine shrimp lethality test; Phytochemical analysis; Msambweni district; Kenya

Ethnodiagnostic Skills of the Digo Community for Malaria: A Lead to Traditional Bioprospecting

Malaria is a major public health problem that is presently complicated by the development of resistance by Plasmodium falciparum to the mainstay drugs. Thus, new drugs with unique structures and mechanism of action are required to treat drug-resistant strains of malaria. Historically, compounds containing a novel structure from natural origin represent a major source for the discovery and development of new drugs for several diseases. This paper presents ethnophytotherapeutic remedies, ethnodiagnostic skills, and related traditional knowledge utilized by the Digo community of the Kenyan Coast to diagnose malaria as a lead to traditional bioprospecting. The current study was carried out in three Digo villages of Diani sub-location between May 2009 and December 2009. Data was collected using semi-structured interviews, and open and close-ended questionnaires. A total of 60 respondents (34 men and 26 women) provided the targeted information. The results show that the indigenous knowledge of Digo community on malaria encompasses not only the symptoms of malaria but also the factors that are responsible for causing malaria, attributes favoring the breeding of mosquitoes and practices employed to guard against mosquito bites or to protect households against malaria. This knowledge is closely in harmony with scientific approaches to the treatment and control of the disease. The Digo community uses 60 medicinal plants distributed in 52 genera and 27 families to treat malaria. The most frequently mentioned symptoms were fever, joint pains, and vomiting while the most frequently mentioned practices employed to guard against mosquito bites and/or to protect households against malaria was burning of herbal plants such as Ocimum suave and ingestion of herbal decoctions and concoctions. The Digo community has abundant ethnodiagnostic skills for malaria which forms the basis of their traditional bioprospecting techniques

In silico exploration of Lycoris alkaloids as potential inhibitors of SARS-CoV-2 main protease (Mpro)

Coronavirus disease 2019 (COVID-19) is a pandemic whose adverse effects have been felt all over the world. As of August 2022, reports indicated that over 500 million people in the world had been infected and the number of rising deaths from the disease were slightly above 6.4 million. New variants of the causative agent, SARS-CoV-2 are emanating now and then and some are more efficacious and harder to manage. SARS-CoV-2 main protease (Mpro) has essential functions in viral gene expression and replication through proteolytic cleavage of polyproteins. Search for SARS-CoV-2 Mpro inhibitors is a vital step in the treatment and management of COVID-19. In this study, we investigated whether alkaloids with antiviral and myriad other bioactivities from the genus Lycoris can act as SARS-CoV-2 Mpro inhibitors. We conducted a computer-aided drug design study through screening optimal ligands for SARS-CoV-2 Mpro from a list of over 150 Lycoris alkaloids created from online databases such as ChEMBL, PubChem, ChemSpider, and published journal papers. The In silico study involved molecular docking of Lycoris alkaloids to SARS-CoV-2 Mpro active site, absorption, distribution, metabolism, elimination and toxicity (ADMET) screening and finally molecular dynamic (MD) simulations of the most promising ligand-SARS-CoV-2 Mpro complexes. The study identified 3,11-dimethoxy-lycoramine, narwedine, O-demethyllycoramine and epilycoramine as drug-like and lead-like Lycoris alkaloids with favorable ADMET properties and are very likely to have an inhibition activity on SARS-CoV-2 Mpro and may become potential drug candidates. DOI: http://dx.doi.org/10.5281/zenodo.704180

Antimycobacterial and cytotoxic activity of selected medicinal plant extracts

AbstractEthnopharmacological relevanceTuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Several medicinal plants are used traditionally to treat tuberculosis in Ghana. The current study was designed to investigate the antimycobacterial activity and cytotoxicity of crude extracts from five selected medicinal plants.Material and methodsThe microplate alamar blue assay (MABA) was used for antimycobacterial studies while the CellTiter 96® AQueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients were used to compare the activity of crude extracts against nonpathogenic strains and the pathogenic Mycobacterium tuberculosis subsp.tuberculosis.ResultsResults of the MIC determinations indicated that all the crude extracts were active on all the three tested mycobacterial strains. Minimum inhibitory concentration values as low as 156.3µg/mL against M. tuberculosis; Strain H37Ra (ATCC® 25,177™) were recorded from the leaves of Solanum torvum Sw. (Solanaceae). Cytotoxicity of the extracts varied, and the leaves from S. torvum had the most promising selectivity index. Activity against M. tuberculosis; Strain H37Ra was the best predictor of activity against pathogenic Mycobacterium tuberculosis subsp.tuberculosis (correlation coefficient=0.8).ConclusionThe overall results of the present study provide supportive data on the use of some medicinal plants for tuberculosis treatment. The leaves of Solanum torvum are a potential source of anti-TB natural products and deserve further investigations to develop novel anti-TB agents against sensitive and drug resistant strains of M. tuberculosis

In vitro and In vivo antimycobacterial, hepatoprotective and immunomodulatory activity of Euclea natalensis and its mode of action

Ethnopharmacological relevance: The Natal gwarri or Natal ebony (Euclea natalensis A.DC.) is a deciduous tree found widespread throughout southern Africa, especially in Kwazulu-Natal and the southern cost. It has been widely used by indigenous communities such as the Zulus, Tsongas and Vendas for symptoms related to tuberculosis (TB). The decoctions made from the plant parts are administered for chest diseases to treat complications such as chest pains, bronchitis, pleurisy and asthma. TB is prevalent in immune-compromised patients and it is evident that TB-drugs cause hepatotoxicity. The objective of the present study was therefore to evaluate the antimycobacterial activity of the ethanolic extract of E. natalensis against TB and its hepatoprotective and immunomodulatory activities. Materials and methods: The antimycobacterial, antioxidant, hepatoprotective, immunomodulatory activity and cytotoxicity of the ethanolic extract of the shoots of E. natalensis were determined in vitro. The mechanism of action of the antituberculosis activity was determined by investigating the inhibitory effect on mycothiol disulfide reductase enzyme. Furthermore, the acute, sub-acute toxicity (50-2000 mg/kg) and antimycobacterial effect (300 mg/kg) of E. natalensis shoot extract were investigated in Balb/c mice. Hepatoprotective activity of the extract (50-150 mg/kg) was evaluated on isoniazid and rifampicin (50 mg/kg; i.p.) induced hepatic damage in a rat model. Results: The minimum inhibitory concentration of the extract was found to be 125 µg/ml against Mycobacterium tuberculosis. The extracts fifty percent inhibitory concentration (IC50) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical was found to be 22.55 µg/ml. The plant showed a hepatoprotective effect (50% at 12.5 µg/ml) and the ability to increase T-helper 1 cell cytokines; Interleukin 12, Interleukin 2 and Interferon α by up to 12 fold and the ability to decrease the T-helper 2 cell cytokine Interleukin 10 4 fold when compared to baseline cytokine production. No cellular toxicity was observed in primary peripheral blood mononuclear cells (PBMC's) and two secondary cell lines; U937 monocytes and Chang liver cells (a derivative of the HepG2 cell line). During mechanistic studies, the extract showed a 50% inhibition of mycothiol reductase activity at 38.62 µg/ml. During the acute and sub-acute studies, E. natalensis exhibited no toxic effect and the fifty percent lethal dose (LD50) was established to be above 2000 mg/kg. The extract was able to reduce the mycobacterial load (1.5-fold reduction) in infected mice. Isoniazid and rifampicin caused significant hepatic damage in rats, and the extract was able to reduce the toxicity by 15% and 40% at 50 and 150 mg/kg respectively. Conclusion: The present study supports the traditional usage of the plant against tuberculosis symptoms. The study showed the ability of E. natalensis shoot extract to inhibit mycobacterial growth, stimulate an appropriate immune response and have a hepatic protective effect. Due to the extract's significant results for hepatoprotective, immunomodulatory effects and antimycobacterial activity, it may prove to be effective to serve as an adjuvant for TB-patients